A147804 -id:A147804 - cp's OEIS frontend

A147799 Minimal value of A007947(m*(7^n-m)) with m coprime to 7.

6, 6, 30, 30, 282, 2262, 17034, 36006, 71070

Offset: 1

M. F. Hasler, Nov 13 2008

The minima are reached for m values given in A147804.
This is related to the abc conjecture.
All terms of this sequence are even, so one could also consider A147799/2 = 3, 3, 15, 15, 141, 1131, 8517, 18003, 35535, ... So far these terms are also multiples of 3, but this might be a coincidence.

Cf. A007947, A147804 (m values); A143702, A147801, A147800 (analog for 2^n, 3^n, 5^n), A147298 (general case).

A147799(n,p=7)={my(m=n=p^n); for(a=1,n\2, a%p || next; m > 2*A007947(a) || next; m > A007947(n-a)*A007947(a) || next; m = A007947(n-a)*A007947(a)); m; }

A147798 Minimal value of A007947(m*(11^n-m)) with m coprime to 11.

Original entry on oeis.org

6, 30, 30, 390, 3162, 2730, 17706

Offset: 1

M. F. Hasler, Dec 06 2008

The minima are reached for m values given in A147805.

Cf. A007947, A147298, A147799, A147800, A147801, A147802, A147803, A147804, A147805.

A147798(n, p=11) = {my(m=n=p^n); for(a=1, n\2, a%p || next; m > 2*A007947(a) || next; m > A007947(n-a)*A007947(a) || next; m = A007947(n-a)*A007947(a) ); m; }

A147805 Least m coprime to 11 minimizing A007947(m*(11^n-m)).

Original entry on oeis.org

2, 1, 81, 16, 8748, 91, 1489347

Offset: 1

M. F. Hasler, Dec 06 2008

The values of the minima are given in A147798.

Cf. A007947, A147298, A147798, A147799, A147800, A147801, A147802, A147803, A147804.

/* If A147798(n) has already been computed and is stored in a147798[n]: */
A147805(n)={my(m=a147798[n]); for(a=1, n=11^n, a%11 || next; m>2*A007947(a) || next; m==A007947(a)*A007947(n-a) && return(a)) }
/* else use code from A147804 : A147805(n)=A147804(n,11) */

cp's OEIS Frontend

A147799 Minimal value of A007947(m*(7^n-m)) with m coprime to 7.

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A147798 Minimal value of A007947(m*(11^n-m)) with m coprime to 11.

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A147805 Least m coprime to 11 minimizing A007947(m*(11^n-m)).

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PARI